Many people in modem society typically spend extended amounts of time seated at work, school, home, and/or while traveling. In particular, many have jobs that involve continuous sitting in an office environment for many hours. In addition, many people spend large amounts of time in vehicles, frequently traveling many miles in one trip, for example, while commuting to and from work. Furthermore, many people operate vehicles professionally, and accordingly are subjected to even greater amounts of time seated in a vehicle.
Generally, seats have several elements in common. They have a bottom portion, or seat pan, which receives the bulk of a user's weight, and a back portion, against which a user reclines. In addition, to accommodate users of varying proportions and sizes, many seats with a mechanism for adjusting the seat pan and back portion independently or simultaneously. Automobile seals often have such mechanisms, for example.
However, seats generally have insufficient back support, particularly as relates to the lowermost regions of the spine. The spine has four general regions: cervical (neck), thoracic (upper back), lumbar (lower back) and sacral (tail bone). More specifically, the sacrum forms the base of the spine. It is a large triangular fusion of five vertebrae wedged between the pelvic bones. The pelvic bones include the left and right ilium. The ilia each have a posterior border portion known as the posterior superior iliac spine (“PSIS”). The lack of support for the sacrum and a proper nesting configuration for the PSIS often leads to poor posture, and accordingly, varying degrees of discomfort and problems in a user's back or spine regions. Notably, back problems are more likely to occur at the junction of the lumbar spine and the sacrum when a user does not sit up straight.
Sitting up straight can be difficult for the users of seats. In particular, in many seats form a void between the back portion of the seat and the user's sacrum. This void may cause a user to take a slouched position. Slouching, in turn, may lead to a number of immediate problems, for example, increased fatigue, increased pressure on the lumbar discs, or the creation of muscle spasms. Moreover, various long-term problems may also occur as a result of slouching. These problems include pain in the lower back muscles, discomfort between the shoulder blades, tightening of neck muscles and muscle soreness and headaches.
To avoid problems associated with slouching while seated, previous attempts have been made to provide better back support. However, these attempts have failed to provide an adjustable, specific sacral support and contoured fit that will properly position the sacrum, the pelvis, and the supporting neural, muscular, and skeletal systems to provide total pelvic stability. In the past, the void that existed between the sacrum and the back of a seat failed to provide the preferred support for the sacrum and adjoining tissue and was almost entirely ignored by seat manufacturers. Moreover, previous seat manufacturers also ignored the importance of supporting the sacrum while avoiding excessive pressure build-up in the area of the PSIS.
Somewhat recently, it has been recognized that a spinal support device for applying a directed and concentrated force on the sacrum to properly position the pelvis and spine of a user could be constructed. In U.S. Pat. No. 6,125,851 (“the '851 patent”), a spinal support device is disclosed that helps support the sacrum of a user to induce the spine to take the preferable shape found in a normal standing posture. While the '851 patent addresses the void created by seats around the sacral region, there still exists an urgent need to implement proper sacral support integral to seatbacks, such as residential seatbacks, work chairs, commercial seatbacks, and/or vehicular seatbacks. In particular, there exists a need to provide proper sacral support in a system that is integral to a seat and adjusts according to the preferences of a variety of users that differ from each other in proportion and size. In addition, there exists a need to provide proper load distribution across the surrounding pelvic area, and especially as concerns the PSIS. There also exists a need to provide proper sacral support combined with proper lumbar support.